[vbox-dev] call a method runtime

Klaus Espenlaub

2014-05-20 17:01:11 UTC

Johannes,

Post by Johannes DeWitt
Hi, i'm looking for a way to call a method during the execution of
virtualbox (runtime). I read that xpcom or soap can achieve that: in the
source code i can write a method, with special definition and than,
after compiling, i can execute the VM and call this method. Is it correct?
Anyway i read SDK documentation, but i can't find a simple example.

Sounds plausible - but I can't claim I fully understood the problem
description, mostly because it is so short.

Do you really need some API functionality which truly isn't there
already (or can't be triggered by some other means)? Because adding
methods usually means the API compatibility is broken, with the
consequence that your custom code can't be mixed and matched with other
binaries.

One way of triggering activities inside a VM process is by monitoring
extradata change in Console::onExtraDataChange
(src/VBox/Main/src-client/ConsoleImpl.cpp). If this almost matches what
you need it'd be interesting to understand a bit more what you want to
achieve (on a high level - the request to have some new functionality is
relatively low-level and abstract).

If you really really want to add API methods, see e.g.
https://www.virtualbox.org/changeset/48879/vbox

This change adds a new method to IMachine and a new attribute to
IMediumAttachment (consider the change to VirtualBox.xidl the starting
point - that's our abstract API definition, kind of a meta-IDL), plus
settings handling and what not... still one of the simpler API changes.

These new API methods are used by
https://www.virtualbox.org/changeset/49190/vbox which calls the method
from VBoxManage etc etc.

Hope this gives enough hints. Adding APIs is in many ways mostly typing
effort. The real complexity is that one needs to understand quite a bit
of the sometimes not so trivial dependencies by other code or by
(XP)COM. In latest trunk the almost completed transition to
automatically generated API wrappers adds quite some "invisible" magic
and adjusts a lot of conventions. Again more to understand before one
can produce anything but compiler errors.

Post by Johannes DeWitt
Sorry for the bad syntax, but i'm not english.

As long as we can understand the core of your message we won't complain.

Klaus

Post by Johannes DeWitt
Thanks